Elucidating the linkage between changes of marine ecosystems and deposition of deep sea mud highly enriched in rare earth elements

2022 Fiscal Year Final Research Report

• Project/Area Number: 21K20354
• Research Category: Grant-in-Aid for Research Activity Start-up
• Allocation Type: Multi-year Fund
• Review Section: 0202:Condensed matter physics, plasma science, nuclear engineering, earth resources engineering, energy engineering, and related fields
• Research Institution: Chiba Institute of Technology
• Principal Investigator: Mimura Kazuhide 千葉工業大学, 次世代海洋資源研究センター, 主任研究員 (10909435)
• Project Period (FY): 2021-08-30 – 2023-03-31
• Keywords: 海底鉱物資源 / レアアース泥 / 微化石 / 機械学習

Outline of Final Research Achievements

This study aimed to elucidate the linkage between deposition of deep-sea mud highly enriched in rare earth elements, termed as REE-rich mud, and changes of marine ecosystems. In this study, deep-learning based system to detect microfossil fish teeth and denticles, called “ichthyoliths” from microscopic images, was constructed. Using the system, ichthyoliths were observed from deep-sea sediments obtained at various areas of the Pacific Ocean. Based on the observation, it was suggested that redeposition of older sediments affected the occurrence of mud high grade REE-rich mud.

Free Research Field

資源地球学

Academic Significance and Societal Importance of the Research Achievements

イクチオリスを用いた海洋生態系変遷史の解読は近年大きな注目を集めているが，熟練の技術を持つ観察者が時間をかけて実施する必要があることから十分な観察が進んでいなかった．本研究で確立した観察技術により，網羅的なイクチオリス観察が可能になり，今後層序学や古環境学の議論を大きくアップデートすることが期待される．さらに，この技術はあらゆる微化石や粒子鉱物の観察に適用可能であることから，学術的・社会的意義の大きい成果であるといえる．